Many earlier problems with Boeing 787 batteries

Even before two battery failures led to the grounding of all Boeing 787 jets this month, the lithium-ion batteries used on the aircraft had experienced multiple problems that raised questions about their reliability.

Officials at All Nippon Airways, the jets’ biggest operator, said on Tuesday it had replaced 10 of the batteries in the months before fire and smoke in two cases caused regulators around the world to ground the jets.

The airline said it told Boeing of the replacements as they occurred but was not required to report them to safety regulators because no flights were cancelled. National Transportation Safety Board officials said the battery replacements were now part of their inquiry.

The airline also, for the first time, explained the extent of the previous problems, which underscore the volatile nature of the batteries and add to concerns about whether Boeing and other aircraft manufacturers will be able to use them safely.

In five of the 10 replacements, All Nippon said the main battery showed an unexpectedly low charge. An unexpected drop in a 787’s main battery also occurred on the All Nippon flight that made an emergency landing in Japan on January 16. The airline also revealed that in three instances the main battery failed to start normally and had to be replaced, along with the charger.

In other cases, one battery showed an error reading and another, used to start the auxiliary power unit, failed. All occurred from May to December last year and all the batteries were returned to their maker, GS Yuasa.

A spokeswoman for the US National Transportation Safety Board, Kelly Nantel, said investigators had only recently heard of “numerous issues with the use of these batteries" on 787s. She said the board had asked Boeing, All Nippon and other airlines for information about the problems. “That will absolutely be part of the investigation."

Boeing has said repeatedly that any problems with the batteries can be contained without threat to the planes and passengers.

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But in response to All Nippon’s disclosures, Boeing officials said the airline’s replacement of the batteries also suggested that safeguards to prevent dangerous overheating of the batteries might have kicked in.

Boeing officials also said the new batteries were not lasting as long as intended. But All Nippon said the batteries it replaced had not expired.

A GS Yuasa official, Tsutomu Nishijima, said battery exchanges were part of the normal operations of a plane but would not comment further.

The Federal Aviation Administration decided in 2007 to allow Boeing to use the lithium-ion batteries instead of older, more stable types as long as it took safety measures to prevent or contain a fire. But once Boeing put in those safeguards, it did not revisit its basic design, even as more evidence surfaced of the risks involved, regulators said.

In a little-noticed test in 2010, the FAA found that the kind of lithium-ion chemistry that Boeing planned to use – lithium cobalt – was the most flammable of several possible types. The test found that type of battery provided the most power, but could also overheat more quickly.

And in 2011, a lithium-ion battery on a Cessna business jet started smoking while it was being charged, prompting Cessna to switch to traditional nickel cadmium batteries.

The safety board said on Tuesday it had still not determined what caused a fire on January 7 on a Japan Airlines 787 that was parked at Logan Airport in Boston. The fire occurred nine days before an All Nippon jet made its emergency landing when pilots smelt smoke in the cockpit.

Federal regulators said it was also still possible that flaws in the manufacturing process could have gone undetected and triggered the recent incidents.

The battery maker X-rays each battery for possible defects before shipping them.